It replaces the mSATA standard, which uses the PCI Express Mini Card physical card layout and connectors. 2’s more flexible physical specification allows different module widths and lengths, and, paired with the availability of more advanced interfacing features, makes the M. 2 more suitable than mSATA for solid-state storage applications in general and particularly for the use in small devices such as ultrabooks or tablets. Computer bus interfaces provided through the M.

2 connector are PCI Express 3. It is up to the manufacturer of the M.

2 host or device to select which interfaces are to be supported, depending on the desired level of host support and device type. 2 connector has different keying notches that denote various purposes and capabilities of M. 2 hosts and modules, preventing plugging of M. 2 modules into feature-incompatible host connectors.

A high-level overview of the SATA Express software architecture, which also applies to M. It supports both legacy SATA and PCI Express storage devices, with AHCI and NVMe as the logical device interfaces. Buses exposed through the M. 2 connector are PCI Express 3.